When using the CSV file import, there is no limit to the amount of products you can import to your 3dcart store. However, please keep in mind of other factors which will affect the number of products you import at a given time. For example:

Account Limits

Some of our plan offerings do specify limits on the amount of product you can offer in the store altogether. While the CSV import itself does NOT contain a limit to the number of items that can be imported, the account type itself may be overriding the amount of product listings. Click here to review our plan offerrings and their respective product limits.

Again, the import script itself doesn't limit the amount of product you can import, but check to make sure your actual commerce plan itself is equipped to handle the amount of product's you're importing.

File Size

In some cases, the actual size of the file itself may prevent you from importing successfully. Please keep in mind that the import process itself is being done via web browser and may time out if the file is extraordinarily large. Therefore, you may need to consider splitting up the files into smaller increments to accommodate an import. For example, let's say you have 25,000 items in your store and you export the CSV file. If your products contain information like extra fields and extended descriptions written in HTML, there's a good chance your base CSV file will be in the 25 to 50Mb range. Instead of importing a 50Mb CSV file which would likely time out, you can split up the CSV into three separate files of about 5,000 products each to ease the connection.

Furthermore, if your import is being performed to update only certain portions of your product listings, the import CSV file itself can be edited to remove some of the superfluous items that do NOT need to be updated at that time. For example, let's say you're simply using the import to update your product prices; The same 15,000 Product file referenced above will shrink down to just over 1Mb simply by removing ALL columns except [catalogid], [id], [name], and [price]. (In this case, the price column would contain your updated prices)

In closing

So, while the CSV import script itself does not limit the amount of products you are able to import, there are in some case other factors which may prevent a successful import. The two factors listed above are by far the most common.